(univ_tvs, _, eq_spec, _, _, data_ty) = dataConFullSig con1
-- For a data type family, the data_ty (and hence selector_ty) mentions
-- only the family TyCon, not the instance TyCon
(univ_tvs, _, eq_spec, _, _, data_ty) = dataConFullSig con1
-- For a data type family, the data_ty (and hence selector_ty) mentions
-- only the family TyCon, not the instance TyCon